A. Field of Invention
This invention pertains to the art of methods and apparatuses for snowplows and more specifically to a modular hydraulic power mechanism that is used to provide hydraulic power to a snowplow system.
B. Description of the Related Art
It is well known in the art to provide snowplow systems for use in moving snow from roads, driveways, parking lots and other such surfaces. Typically, the snowplow system is attached to a vehicle such as a pickup truck. Usually, the snowplow can be moved by the driver/operator of the vehicle. Thus, for example, the operator can adjust a control system from inside the occupant compartment of the vehicle to raise and lower the snowplow and pivot the snowplow.
In recent years, the snowplow industry has provided additional snowplow designs and movement options. A relatively new snowplow, for example, is termed a V-plow and is essentially two plows combined onto a single frame. In this case, each plow is generally considered a wing and typically each wing can be controlled independent of the opposite wing. Another known type of plow consists of a middle portion which cannot be pivoted and a pair of pivotable wings on each end. Most often snowplows are moved using a hydraulic system. As a result, hydraulic components such as hydraulic cylinders, hydraulic piping and hoses, appropriate fittings and the like are required to operate the snowplow. A hydraulic power mechanism is also generally provided to receive some type of control signal from the operator and convert that signal into the appropriate movement of the hydraulic components so that the snowplow is positioned properly. Such hydraulic power mechanisms are known to include a base plate, a hydraulic reservoir or tank, a hydraulic pump unit, and the necessary control valves such as solenoid valves and/or cartridge valves. Such known hydraulic power mechanisms work well for their intended purpose.
One known difficulty, however, with known hydraulic power mechanisms is that a separate power mechanism is required for each snowplow system arrangement. Thus, for example, one hydraulic power mechanism is appropriate for a standard plow while a second hydraulic power mechanism is required for a V-plow. A third hydraulic power mechanism is required for the plow having a middle portion which cannot be pivoted and a pair of pivotable wings on each end. Other snowplow designs require yet additional separate hydraulic power mechanisms. This requirement for a large number of hydraulic power mechanisms forces snowplow system distributors to maintain a large inventory. This increases the need for inventory space and adds to the expense of the snowplow systems.
This difficulty is partially addressed in U.S. Pat. No. 3,773,074, titled HYDRAULIC CONTROL UNIT (the '074 patent), which has a common assignee to this patent application and which is incorporated herein by reference. The '074 patent provides a power unit having a base portion with a sidewall. To the sidewall different control blocks may be attached to provide corresponding different snowplow functions. While the power unit of the '074 patent works well for its intended purpose, it has limitations. One limitation is that the power unit is defined by a reservoir ram unit in which a lift cylinder is positioned. The area around the lift cylinder defines the hydraulic fluid reservoir. This incorporation of the lift cylinder with the power unit limits the range of modular adjustment available and positions the reservoir above the base portion. Another limitation of the power unit of the '074 patent is that the different control blocks must be attached to the side of the base portion. This “sideways” design makes modular adjustment more difficult.
The present invention minimizes these difficulties by providing a modular hydraulic power mechanism that can be simply modified to accommodate a wide range of snowplow systems and where the hydraulic components do not define any portion of the hydraulic power mechanism.